Method of making carpet underlay

ABSTRACT

A method of making a carpet underlay is provided wherein the underlay is comprised of a sponge rubber body having a load-carrying surface defined by a plurality of cooperating closed-area coplanar portions which define the major part of the area of a plan view of such body.

This is a division of application Ser. No. 380,429, filed July 18, 1973.

BACKGROUND OF THE INVENTION

There are numerous types of carpet underlay in present use which attemptto give a carpet associated therewith the feeling that it is made of adeeper and more luxurious pile and such present underlay ranges fromsheets of compressible material having opposed parallel planaruninterrupted surfaces to sheets of compressible material having spacedupwardly convex or dome-like surfaces provided therein which define atop load-carrying surface. In general, the carpet underlay of thefirst-mentioned type does not provide the desired luxurious feeling forits associated carpet while carpet underlay of the second type does notprovide a completely satisfactory load-carrying surface.

SUMMARY

This invention provides a method of making an improved carpet underlay,wherein the carpet underlay is comprised of a sponge rubber body havinga load-carrying surface defined by a plurality of cooperating coplanarportions which define the major portion of the area of a plan view ofsuch body; and, such carpet underlay provides a load-carrying surface ofmaximum area while providing a luxurious feeling for its associatedcarpet even though such carpet may be comparatively inexpensive.

Other details, uses, and advantages of this invention will be readilyapparent from the embodiments thereof presented in the followingspecification, claims, and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings show present preferred embodiments of thisinvention, in which

FIG. 1 is a view with parts in elevation, parts in cross-section, partsbroken away, and parts shown schematically of one exemplary embodimentof an apparatus and method of this invention which may be used to makeone exemplary embodiment of the improved carpet underlay of thisinvention, and which utilizes improved means for supporting a sheet ofmaterial used to define the carpet underlay;

FIG. 2 is a plan view illustrating a fragmentary part of the supportingmeans comprising the apparatus of FIG. 1 and such supporting means isdefined by a mesh material and cooperating elongated strip means withcertain ones of such strip means being removed to better illustrate themesh material;

FIG. 3 is a fragmentary plan view similar to FIG. 2 illustrating anotherembodiment of supporting means which may comprise the apparatus of FIG.1 and which employs another embodiment of a mesh material which may usetwo exemplary types of elongated strip means; and, also illustrating acertain portion of the mesh material with the strip means removed.

FIG. 4 is a view with parts in cross section and parts broken away takenessentially on the line 4--4 of FIG. 3 particularly illustrating oneembodiment of strip means installed in the mesh material in oneposition;

FIG. 5 is a view similar to FIG. 4 illustrating strip means installed inthe mesh material in another position to define another exemplaryembodiment of carpet underlay;

FIG. 6 is a view similar to FIG. 4 illustrating another exemplaryembodiment of elongated strip means having a formed central portion andbeing installed in the mesh material;

FIG. 7 is a fragmentary plan view illustrating one exemplary embodimentof a carpet underlay of this invention made using the apparatus andmethod of FIG. 1;

FIG. 8 is a view similar to FIG. 7 illustrating another exemplaryembodiment of carpet underlay of this invention;

FIG. 9 is a view similar to FIG. 7 illustrating another exemplaryembodiment of carpet underlay of this invention;

FIG. 10 is a view similar to FIG. 7 illustrating another exemplaryembodiment of carpet underlay of this invention;

FIG. 11 is a cross-sectional view not drawn to exact scale and beingtypical of a cross-sectional view taken essentially on the line of11--11 of each of FIGS. 7, 8, 9, and 10;

FIG. 12 is a cross-sectional view also not drawn to exact scale andbeing typical of a cross-sectional view taken essentially on the line12--12 of each of FIGS. 7, 8, 9, and 10;

FIG. 13 is a view similar to FIG. 7 illustrating still another exemplaryembodiment of carpet underlay of this invention; and

FIG. 14 is a view taken essentially on the line 14--14 of FIG. 13.

DESCRIPTION OF ILLUSTRATED EMBODIMENTS

Reference is now made to FIGS. 7 and 11-12 of the drawings whichillustrate one exemplary embodiment of the improved carpet underlay ofthis invention which is designated generally by the reference numeral 20and such carpet underlay comprises a sponge rubber body having asubstantially planar load-carrying surface as indicated generally at 21which is defined by a plurality of spaced apart cooperating closed-areacoplanar portions each designated by the same reference numeral 22. Eachportion 22 is arranged in at least one associated row 23 with each pairof immediately adjacent portions in the row 23 being interconnected byan associated integral roughly U-shaped portion 24, see FIG. 11, whichdefines a channel 25 between the pair of immediately adjacent portions22.

The portions 22 in the exemplary carpet underlay 20 are arranged in aplurality of parallel rows which for convenience will also be designatedby the same reference numeral 23. Further, a pair of immediatelyadjacent portions 22 in adjacent parallel rows 23 are alsointerconnected by roughly U-shaped portions 26 of the sponge rubber bodyas illustrated in FIG. 12 and each U-shaped portion 26 also defines achannel 27 between such immediately adjacent coplanar portions 22.

The carpet underlay 20 has a backing material which may be a woven scrimmaterial or other suitable non-woven backing material, which isdesignated by the reference numeral 28 in FIGS. 11 and 12 and thematerial is suitably bonded or fixed as by heat sealing or similarprocess against the outer surfaces 29 of the bights of U-shaped portions24 and 26.

The load-carrying surface 21, defined by the combined or total areas ofclosed-area coplanar portions 22, comprises a substantial part of thetotal area of a plan view of the carpet underlay 20, as viewed in FIG. 7for example. In particular, such combined areas may define from 50 to ashigh as 90 percent of the total area of such plan view which is definedby the combined areas of the coplanar portions 22 plus the areas asviewed in plan view of the channels 25 and 27.

Having described one exemplary embodiment of the carpet underlay of thisinvention, the detailed description will now proceed with a descriptionof an improved apparatus and method which is designated generally by thereference numeral 35 in FIG. 1 and which may be used to make the carpetunderlay 20. The apparatus 35 includes a device for providing acontrolled environment for a web or sheet 36 of elastomeric materialwhich is capable of foaming and vulcanizing and is adapted to define thecarpet underlay 20 and such device may be in the form of an oven or heattunnel 37 which is particularly adapted to provide a heated environmentfor the sheet 36.

The heat tunnel 37 may of any known construction and is provided withsuitable controls of a type well known in the art to assure that oncethe sheet 36 is passed therethrough it is heated, expanded or spongedand vulcanized or cured in a manner well known in the art to produce thecarpet underlay 20 of this invention.

As shown in FIG. 1, elastomeric material M, such as a rubber material orsuitable plastic material, is processed by cooperating forming rolls 40,for example, or other suitable means, to define the sheet 36 and suchsheet is received on a conveyor assembly 42 which in turn deposits thesheet 36 on the unique supporting means of this invention which isdesignated generally by the reference numeral 43 and which is used tosupport sheet 36 in the heat tunnel 37. The supporting means 43 assuresthe provision of the unique carpet underlay of this invention with itsimproved loadcarrying surface and improved rebound characteristics.

The supporting means 43 is comprised of a mesh material 44, see FIG. 2,having a plurality of undulating members each designated by thereference numeral 45 and each immediately adjacent pair is held togetherby a common tie member 46 to define essentially a woven arrangement. Asshown typically at 50 in FIG. 2 each undulating member 45 is comprisedof a plurality or first set of parallel portions 51 which are adapted tobe arranged in one plane and a plurality or second set of parallelportions 52 which are adapted to be arranged in a second plane which isparallel to the plane of the portions 51.

The supporting means 43 also comprises elongated strip means which inthe example of FIG. 2 are shown as a plurality of elongated flat stripseach designated by the reference numeral 53. Each flat strip 53 issupported by an associated undulating member 45 and in particular hasits opposed large surfaces confined or sandwiched between the portions51 and 52 of such member 45. In addition, each strip 53 has oppositeside edges 54 which are confined between the inside surfaces 55 arrangedopposite from each apex of each undulating member 45 as shown at 56 inFIG. 2. The strips 53 serve to define the coplanar portions 22 as willbe described in detail subsequently.

As mentioned above, the supporting means 43 is comprised of the meshmaterial 44 and the strips 53 and such supporting means is in the formof an endless conveyor which is supported for movement in an endlesspath by a pair of cooperating cylinders each designated by the samereference numeral 60 in FIG. 1. Each cylinder 60 may be provided withsuitable teeth, friction surfaces, or the like, so that upon rotationthereof the supporting means 43 is moved in an endless path with a tophorizontal portion 61 of the supporting means 43 extending through theheat tunnel 37 by moving through suitable openings 62 in opposite endsthereof; and, in this example a lower horizontal portion 63 of thesupporting means 43 is arranged beneath the heat tunnel 37. Any suitablemeans may be provided for moving the endless supporting means orconveyor 43 in its endless path and in this example a motor 65 isoperatively connected by a mechanical connection, shown by dot-dashlines 66, to the shaft 67 of one of the supporting cylinders 60 so thatupon rotating shaft 67 with the motor 65 the supporting means 43 ismoved in an endless path passing the elastomeric sheet 36 carried onhorizontal portion 61 through the heat tunnel 37.

Having described one exemplary embodiment of the carpet underlay 20 ofthis invention and an exemplary apparatus for making same, the detaileddescription will now proceed with a brief presentation of the uniquemethod employed in making such carpet underlay and for this descriptionparticular reference is first made to FIGS. 1 and 2 of the drawings. Inmaking the underlay 20 it will be noted that in the supporting means 43the mesh material 44 is constructed and arranged relative to thecylinder 60 so that the elongated strips 53 are arranged substantiallyperpendicular to the direction of movement 70 of the conveyor throughthe heat tunnel.

Initially a forward end portion of the elastomeric sheet 36 is suitablyattached to and supported on the top horizontal portion 61 of thesupporting means or endless conveyor 43 whereupon motor 65 is energizedto rotate shaft 67 and its associated cylinder 60 to thereby move thesheet 36 of elastomeric material through the heat tunnel 37 in acontinuous manner.

As the sheet 36 moves through the heat tunnel 37 it is acted upon by thecontrolled heated environment thereof causing such sheet to soften anddroop around the undulating members 45 and the tie members 46 of themesh material 44. The heated environment also causes expansion by thegeneration and release of some gases from the sheet 36 as it continuesthrough the heat tunnel 37 and the sheet is vulcanized or suitably heatcured.

Simultaneously with the expansion and heat curing of the sheet 36 theupper portions 52 of the undulating members 45 define channels 25 andcause the formation of U-shaped portions 24. Similarly, the tie members46 define channels 27 and cause the formation of U-shaped portions 26.Finally, the strips 53 limit the drooping and control the expansion ofthe heated sheet to define the plurality of coplanar portions 22 whichdefine the substantially planar load-carrying surface 21 of the carpetunderlay 20.

The use of the strips 53 also assures that the sheet 36 will not droopand extend completely through the mesh material 44 as the sheet is movedthrough the heat tunnel 37 making it impossible with this constructionof supporting means for the sheet 36 to droop and/or expand completelythrough the mesh material 44; and, this latter situation is a problemwith apparatus proposed previously which only use mesh-type supports. Inparticular, such previously proposed apparatus often use flat supportingbeds beneath the mesh supports and even with this added complexity insuch previous apparatus the sheet stock generally droops completelythrough its mesh support requiring the sheet to be dragged across itssupporting bed and thereby causing unsatisfactory movement and theproduction of an unsatisfactory carpet underlay.

Other exemplary embodiments of carpet underlay of this invention areillustrated in FIGS. 8, 9, 10, and 13-14. The embodiments of carpetunderlay illustrated in FIGS. 8, 9, 10, and 13-14 ae similar to thecarpet underlay 20; therefore, such embodiments of carpet underlay willbe designated by the reference numerals 20A, 20B, 20C, and 20Drespectively and representative parts of each carpet underlay which aresimilar to corresponding parts of the carpet underlay 20 will bedesignated in the drawings by the same reference numeral as in thecarpet underlay 20 (whether or not such representative parts arementioned in the specification) followed by an associated letterdesignation, eithe A, B, C, or D and not described again in detail.

The carpet underlay 20A has a substantially planar load-carrying surface21A defined by a plurality of cooperating coplanar portions 22A and thecoplanar portions 22A are arranged in a plurality of parallel rows 23Awith each pair of immediately adjacent portions 22A in one row 23A beinginterconnected by an associated integral roughly U-shaped portion whichis substantially identical to the portion 24 of underlay 20 and definesa channel 25A between the immediately adjacent portions. The carpetunderlay 20A also has channels 27A therein defined by integral U-shpedportions similar to the U-shaped portions 26 of the carpet underlay 20.The carpet underlay 20A is made utilizing the apparatus and method 35and supporting means 43. The supporting means 45 is modified slightly byconstructing and arranging the mesh material 44 thereof so thatelongated strips used therewith extend substantially parallel to thedirection of the movement 70, also shown in FIG. 8. The positions thatsuch elongated strips would normally be arranged in the mesh materialare shown at a few typical locations relative to the carpet underlay 20Ain FIG. 8 by dot-dash lines and designated by the reference numeral 53A.

The carpet underlay material 20B, shown in FIG. 9, also has asubstantially plnar load-carrying surface 21B which is defined by aplurality of cooperating coplanar portions 22B. Each portion 22B isarranged in at least one row 23B with each pair of immediately adjacentportions 22B in the one row being interconnected by an associatedintegral U-shaped portion similar to the U-shaped portion 24 to define achannel 25B therebetween. The associated pair of immediately adjacentportions 22B in a pair of rows 23B are interconnected by U-shapedportions similar to portion 26 to define a channel 27A therebetween.

The carpet underlay 20B is preferably made using the apparatus andmethod 35 modified to utilize the modified mesh material 44 and formedstrip means or elongated strips 53B as shown in the bracketed centralportion 71 of FIG. 3. Each strip 53B has a formed central portion, alsosee FIG. 6, defined by an upstanding projection 72 and the projection 72defines corresponding channels 73B in the carpet underlay 20B. Thestrips 53B utilized in association with the mesh material 44 of FIG. 3are arranged so that they extend perpendicular to the direction ofrectilinear movement 70 of the mesh material 44 through the heat tunnel37.

The carpet underlay 20C illustrated in FIG. 10 has a substantiallyplanar load-carrying surface 21C defined by a plurality of cooperatingcoplanar portions 22C. Each of the coplanar portions is arranged in theleast one row 23C with each pair of immediately adjacent portions in onerow being interconnected by as associated roughly U-shaped portion whichdefines a channel 25C therebetween. The coplanar portions 22C arearranged in a plurality of rows 23C and a pair of adjacent portions 22Carranged in a pair of rows are interconnected by an associated roughlyU-shaped portion which defines a channel 27C therebetween.

The carpet underlay 20C is preferably made utilizing the apparatus andmethod 35 which employs modified mesh material 44, illustrated in thebracketed upper portion 74 of FIG. 3, and flat strips 53C held betweenportions 51 and 52 of the undulating members 45 and confined between tiemembers 46, also see FIG. 4. The carpet underlay 26C is defined byarranging the flat strips 53C as illustrated in FIG. 4 and it will beseen that, if desired, the tie members 46 need not necessarily be madeas illustrated at 76 in FIG. 3 with a comparatively few undulations;but, may be made as illustrated at 77 with a comparatively larger numberof undulations. The larger number of undulations as shown at 77effectively increase (double in this example) the points at which a tiemember 46 engages a strip, such as 53C, as shown at 80, to help holdsuch strip in position in a firmer manner.

The carpet underlay 20D illustrated in FIG. 13 is preferably madeutilizing the apparatus and method 35 while using the mesh material 44and the elongated strips arranged as shown in the bracketed upperportion of FIG. 3. Such strips are designated by the reference numeral53D in FIG. 5.

The carpet underlay 20D also has a substantially planar load-carryingsurface 21D defined by a plurality of cooperating coplanar portions 22D.The coplanar portions 22D are arranged in rows 23D and a pair ofimmediately adjacent portions 22B in one row are interconnected by anassociated roughly U-shaped portion 24D as shown in FIG. 14 to define achannel 25D between the pair of immediately adjacent portions 22D in theone row. The channel 25D has a central portion which is closed, asillustrated at 79D and the opposite ends 81D of such channel are openwhereby with this construction a maximum load-carrying surface isprovided for the carpet underlay 20D which has properties of rebound orresilience and a yielding character substantially similar tocorresponding properties of each carpet underlay 20 and 20A-20C; yet,the carpet underlay 20D has strength and which approaches the strengthof a substantially solid piece of sponge rubber carpet underlay having auniform thickness throughout and a pair of opposed continuous oruninterrupted planar surfaces.

The mesh material 44 illustrated in each of FIGS. 2 and 3 may be made ofany suitable material and in general such mesh material may be made of ametal wire or may be made of any suitable nonmetallic material capableof being passed through the heat provided by the heat tunnel 37 withoutdetriment thereto.

The elongated strip material or strips 53, 53A, 53B, 53C and 53D aremade of any suitable material which is reasonably bendable yet resilientand capable of withstanding the temperatures of the heat tunnel 37. Ingeneral, each of these elongated strips must be capable of withstandingbetween 250° and 500° F. and may be made of metal, teflon, siliconecoated glass cloth, and which may be of solid or porous construction.

In some applications of this invention a woven metal cloth of 60 to 100mesh, a porous teflon, or a porous silicone coated glass cloth may beprovided to define the strips to assure that gases released from thesheet of elastomeric material 36 in tunnel 37 are not trapped beneatheach planar portion, such as 22, of the carpet underlay defined by suchsheet. However, regardless of the material used to define each strip itis preferably made so that it has a minimum thickness which is generallyof the order of 0.020 inch thick and is indicated by the letter T inFIG. 4, for example.

Thus, it is seen that various embodiments of improved carpet underlayare provided by this invention as well as an improved apparatus andmethod for making same. Further, the carpet underlay produced by thisinvention has a comparatively large load-carrying surface defined by aplurality of coplanar portions which may comprise as much as 90% of thetotal area of a plan view of such carpet underlay.

While present exemplary embodiments of this invention and methods ofpracticing the same, have been illustrated and described, it will berecognized that this invention may be otherwise variously embodied andpracticed within the scope of the following claims.

1. A method of making carpet underlay comprising the steps of forming anendless conveyor means of heat resistor wire-like mesh material havingopenings with heat resistant elongated flat strips inserted therein,forming a sheet of elastomeric material, depositing said sheet on saidmesh material, heating said sheet to soften it and to cause it to drooparound said mesh material, forming a plurality of U-shaped channels inthe upper surface of said sheet as a result of said droop, limiting saiddroop on the lower surface of said sheet by means of said strips,further utilizing said strips to prevent said sheet from passingcompletely through said openings in said mesh material andsimultaneously expanding
 2. The method of claim 1 in which said step ofheating is provided by a
 3. The method of claim 1 including the step offorming said mesh material into a plurality of undulating members heldtogether by common tie members to form said openings.